chore: add .gitignore and .gitattributes

.gitignore covers env/secrets, OS files, IDE, Go build artifacts,
frontend build output, data dirs, and vendored reference libs.
.gitattributes enforces LF line endings, marks binaries, configures
diff drivers per language, and sets Linguist hints for repo stats.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitattributes

@@ -0,0 +1,67 @@
+# =============================================================================
+# Tanabata File Manager — .gitattributes
+# =============================================================================
+
+# ---------------------------------------------------------------------------
+# Line endings: normalize to LF in repo, native on checkout
+# ---------------------------------------------------------------------------
+* text=auto eol=lf
+
+# ---------------------------------------------------------------------------
+# Explicitly text
+# ---------------------------------------------------------------------------
+*.go        text eol=lf
+*.mod       text eol=lf
+*.sum       text eol=lf
+*.sql       text eol=lf
+*.ts        text eol=lf
+*.js        text eol=lf
+*.svelte    text eol=lf
+*.html      text eol=lf
+*.css       text eol=lf
+*.json      text eol=lf
+*.yaml      text eol=lf
+*.yml       text eol=lf
+*.md        text eol=lf
+*.txt       text eol=lf
+*.env*      text eol=lf
+*.sh        text eol=lf
+*.toml      text eol=lf
+*.xml       text eol=lf
+*.svg       text eol=lf
+Dockerfile  text eol=lf
+Makefile    text eol=lf
+
+# ---------------------------------------------------------------------------
+# Explicitly binary
+# ---------------------------------------------------------------------------
+*.png       binary
+*.jpg       binary
+*.jpeg      binary
+*.gif       binary
+*.webp      binary
+*.ico       binary
+*.ttf       binary
+*.woff      binary
+*.woff2     binary
+*.eot       binary
+*.otf       binary
+*.zip       binary
+*.gz        binary
+*.tar       binary
+
+# ---------------------------------------------------------------------------
+# Diff behavior
+# ---------------------------------------------------------------------------
+*.sql       diff=sql
+*.go        diff=golang
+*.css       diff=css
+*.html      diff=html
+
+# ---------------------------------------------------------------------------
+# Linguist: set repo language stats correctly
+# ---------------------------------------------------------------------------
+docs/reference/** linguist-documentation
+frontend/static/** linguist-vendored
+*.min.js linguist-vendored
+*.min.css linguist-vendored

.gitignore

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+# =============================================================================
+# Tanabata File Manager — .gitignore
+# =============================================================================
+
+# ---------------------------------------------------------------------------
+# Environment & secrets
+# ---------------------------------------------------------------------------
+.env
+.env.local
+.env.*.local
+*.pem
+*.key
+
+# ---------------------------------------------------------------------------
+# OS
+# ---------------------------------------------------------------------------
+.DS_Store
+Thumbs.db
+Desktop.ini
+*.swp
+*.swo
+*~
+
+# ---------------------------------------------------------------------------
+# IDE
+# ---------------------------------------------------------------------------
+.vscode/*
+!.vscode/extensions.json
+!.vscode/settings.json
+.idea/
+*.iml
+*.sublime-project
+*.sublime-workspace
+
+# ---------------------------------------------------------------------------
+# Backend (Go)
+# ---------------------------------------------------------------------------
+backend/tmp/
+backend/cmd/server/server
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+*.test
+*.out
+*.prof
+coverage.out
+coverage.html
+
+# ---------------------------------------------------------------------------
+# Frontend (SvelteKit / Node)
+# ---------------------------------------------------------------------------
+frontend/node_modules/
+frontend/.svelte-kit/
+frontend/build/
+frontend/dist/
+frontend/src/lib/api/schema.ts
+
+# ---------------------------------------------------------------------------
+# Docker
+# ---------------------------------------------------------------------------
+docker-compose.override.yml
+
+# ---------------------------------------------------------------------------
+# Data directories (runtime, not in repo)
+# ---------------------------------------------------------------------------
+data/
+*.sqlite
+*.sqlite3
+
+# ---------------------------------------------------------------------------
+# Misc
+# ---------------------------------------------------------------------------
+*.log
+*.pid
+*.seed
+
+# ---------------------------------------------------------------------------
+# Reference: exclude vendored libs, keep design sources
+# ---------------------------------------------------------------------------
+docs/reference/**/bootstrap.min.css
+docs/reference/**/bootstrap.min.css.map
+docs/reference/**/jquery-*.min.js
+docs/reference/**/__pycache__/
+docs/reference/**/*.pyc